When inspecting a semiconductor chip using a test program, it is important to perform inspection in a short time as much as possible. From when a test signal is input to a test-signal input pin of a semiconductor chip, it takes a certain period of time until a signal at a signal output pin starts to vary. Moreover, the signal at the signal output pin does not suddenly reach a desired signal level. There is an unstable region in which the signal level is unstable for a while after the signal starts to vary and then moves to a stable region.
For the reason above, conventionally, a test signal is applied to a test-signal input pin of a semiconductor chip to measure a waveform at a signal output pin using measuring equipment such as an oscilloscope. The measured waveform is then analyzed to detect unstable and stable regions, and based on a result of detection, a signal read-in timing is set. This operation has to be done by an operator manually, hence it takes time to perform this operation. Moreover, since this operation has to be performed for each signal output pin, there is a problem in that an operator's burden is increased as the number of pins is increased.